The invention relates to an open roof construction for a vehicle having a roof opening which can be closed by a panel of which at least the rear edge can be pivoted upward and downward, and wherein a body for locally influencing the air flow is provided on the underside of said panel, near said rear edge.
In an open roof construction of the type to which the present invention relates, which comprises a panel whose rear edge can be pivoted upward and downward (a so-called tilt panel), objectionable noises, in particular whistling noises, are produced in the open position of the panel. These noises, which depend on the pivoting angle and the driving speed of the vehicle, among other things, are produced especially (but not exclusively) during the first stage of pivoting the panel from the closed position to an open position. The noises that are produced are highly objectionable to the occupants of the vehicle. The cause of the objectionable noises is to be found inter alia in the underpressure generated above the roof of the vehicle as a result of the air flow over the panel, which causes the air to be drawn out from the interior of the vehicle through a gap that is formed at the location of the upwardly pivoted rear edge of the panel.
In the past, attempts have been made to prevent the occurrence of these objectionable noises. German patent no. 4016791 discloses an open roof construction for a vehicle, wherein the means for locally influencing the air flow is made up of a strip projecting downwards near the rear edge of the panel, on the free ends of which projections are present for influencing the air flow. The function of the strip provided with projections is to disturb coherent flow structures through the aforesaid gap. The means used in this prior art solution has a substantially two-dimensional shape (after all, with a minimum dimension in the direction of flow), whose dimension in a direction perpendicular to the panel surface is considerable. Accordingly, one drawback of this prior art solution is the fact that the obstruction in the gap that is formed by said means needs to be compensated by a greater pivoting movement of the rear edge of the panel if it is desired to maintain an unchanged effective gap between the rear edge of the panel and the roof of the vehicle. The increased pivotability, however, makes it necessary to adapt the technical construction of the panel (in particular the parts thereof that are to effect the movement of the panel) with all the concomitant drawbacks thereof (among which an increased space requirement for construction parts, higher cost, etc.).